{"schema":"pubphys.bundle/1","record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"b2e60c411e3e050c340636139e2cb3b4f7116dd0fe4e58b83a0cacb412646d51","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["84ce1c7bc46a6b9febd203bba7fde4af888b1a1871f94c4879fdfe4060d3970b","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"dd121813de63e3f62db282bea91ef60e9321d8a171fdf732eab780e5281c0814","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"nuc.precision-anomalies.x17-anomaly-origin","kind":"phenomenon","literature_status":"contested","n":"2","parents":[],"plain":"A group in Hungary (ATOMKI) saw too many electron-positron pairs emitted at large angles from excited beryllium, helium and carbon nuclei, as if a new particle of about 17 MeV were produced. Other experiments have not confirmed it.","posed_since":"2016","precise":"ATOMKI reported excesses in the e+ e- opening-angle distribution from internal pair creation in the 18.15 MeV 8Be (2016), 20.21 MeV 4He and 17.23 MeV 12C transitions, each consistent with a boson of mass about 16.7 to 17.0 MeV. Determine the origin: a new boson (X17), a standard nuclear-physics effect, or an instrumental artifact. Answer: the identified origin with independent experimental confirmation.","problem_ref":"84ce1c7bc46a6b9febd203bba7fde4af888b1a1871f94c4879fdfe4060d3970b","references":"","settled_by":"Independent repetition of the 8Be and 4He pair-emission measurements with different detectors, combined with direct searches for a 17 MeV boson coupled to electrons.","status_note":"MEG II (2024) found no signal in $7\\mathrm{Li}(p, e+ e-)8\\mathrm{Be}$ and set 90 percent CL limits $R < 1.8 \\times 10^{-6}$ ($17.6\\,\\mathrm{MeV}$) and $R < 1.2 \\times 10^{-5}$ ($18.1\\,\\mathrm{MeV}$) on the X17 branching ratio relative to gamma emission, while PADME (2025) reported an excess near $16.90\\,\\mathrm{MeV}$ with a global significance of about 2 standard deviations.","title":"Origin of the ATOMKI 17 MeV pair-emission anomaly","topic_ref":null},"content_withheld":"false","files":[],"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"c88e47e949db3662e82d801e83482f62f036fda11dc7ede1d009664c218794a2","schema":"pubphys.attested/1"},"id_token":null,"id_token_withheld":"false","envelope":{"attested_hash":"37383f405b602cd17c2224e4e515f109c3cddd91702eed82f61057226cc1cd48","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"D7bZKGDGge58Fwl5qC2MhmZPBAUnuVvbbsO1iMEFVqykzV5pPweKf0KjbmqqVRzfowschKghLLH4xACroEK0CQ"},"schema":"pubphys.envelope/1"},"ots":{"attested":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEINzg_QFtgLNF8IiTk5RXxCcPN3ZFwLu2C9hBXImzBzUjxIDc1qwanrT8dOIFUbYkUewuDR-czeg_eAHuV-qFSkGZfCPAg1nAPHKh-LTi2v6fLVQ2RQnqLrYtKfi9kxhbJCVywZNsI8SCgsdjskjvWPwnwx-QkjwALTm1MShpd_tncCwlFZ44aJwjxICqtf3ALINcvUFscaDG17FKtB0ZmMWgGMP1tNu81eDdXCPAgesglhxbuAuzg6RWLMSgPDFn9ng6kfra7iC_q9S4i518I8SCQM25n-lK5RW_DOQVDJtOJg6oOsJpwYPY8FgHAN0TjgwjxIEQEcfof0fTRSONQtK0JcKN996uK3Kq9FGO8vxPBfScPCPEgET84erh4QMqfDxFWGLBJaZS5EYFN7oYAm7iWbswJgxQI8CDsCcIzBovmyR1v7IXhYg1Z7m0X4dWZvLS_NU94HSk3sQjxIJdQdDsL3v2lA7qZb8kMJtOgaTQmbgchdPcS5lYJqDLnCPAgkPXX-naXR0fRIdS-sEDlzYmtMvSCNH42ESUF0QXb6NUI8CDQo_sIWZiWXaTGRSQBLmU-lHJKskYKqsjO1r02DhB8LAj_8Ajn9YmozHwo9QjwEJ46aM9ZDv3TdtqV3ZbRsNgI8SBOF8pILGf1kodr5MKmQs6Cd93joraGn3g6UPt_-kewPwjwIOG-gmM7bd_eR4AiDMNfluS3xvr7vicLR-sCBr5qtG2cCPAgrVNFrCoeQcCxhlmnE0BzHgR8HQpZAlfqzDDFzfWb8GUI8QRq0WWT8AjZJ2cF_c7k8ACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AI9ZMS1zxd7IEI8BDd00WgJZ0RncsC1Fyai_4aCPEgvxMFrnu7F05IW5INiraQ3OVEYMjNx6JfBxw1Q4jPLi4I8QRq0WWS8Ag2zxPAtI5JsP8Ag9_jDS75DI4uLWh0dHBzOi8vYWxpY2UuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZwjxIHAnv4KFFf4uiYEFJvLxiMxSyz8VowJP4roTfDD9h7bICPAgj5tgvbNF7mxSP4jGGE66ezUFRLnI4g1VTkvuV4VtCPAI8CCxlc1HuKORuHgn7DYIYcDhc4oo99OkTWBEvddBypoa7AjwIFcjjaF8kDNDYCZGaNISlRjvX-I7in-QNwsr4JYQbFJvCPAgnl0k4gs7LuY5i1umiHO-J7My3uBThLJUWQoY9LdVSrQI8SA6-Ft11_K_GqMNWYhkVsVqCFvXSYbp4S8JoLsLBnUzvgjxIBC8_mAE7JBP35SNxDBcG7joLJwURpMxdV2vSO64_jEOCPEge04Coj1xSi7CE8UwqiBGNhPyZ5QdD_YZwn-heSdObU4I8SBgdDSgr3VUx1j8m_pK7-OzMwwFgXeLy43ujffCv-hf5AjwIMl-PnAt4xjoBEVU4-nkyN0NKRa9AvX4kEMfllFyIJS9CPFZAQAAAAHz4rV-uwQFg02bVnEMUFgpIdGKjM4tWuID1kTVnrjisAAAAAAA_v___wJURAIAAAAAABYAFBFys2oc0-U-bYrC3VulGLzND5fbAAAAAAAAAAAiaiDwBHLTDgAICPEgMJIBYi46xOIuFDwzJ9nOx14ngW5HbglUf65ORpkoIYcICPAgHgGWEGCDHWgscwT92NOoJ7s-ezbPkyiWr2RnYZDC_dwICPAgtffMyyLu-MscJsDc0dzwGspwSrrmvVAnMNgsgWhHClgICPAgMUl1OfBDUwhp5VZjHwVA0nuz1F5HZTUJCHAnM1L1F3MICPAgStK7UWpnrUueV5EaE7uE0y6BLMp6EANmrbhrTqEBZu8ICPAg5LVW7IHtUL5mNOvPx1hOTfLMmqlQ7t9EFW-KDtrISIQICPAgABgXZ6upFU8qiDQKFtQFpqkjKwl0PsxM4JUjVLlDKbkICPAgEwb96FiOhjlbwI8GFZQ4a5GXwxs4bUdqVOMKrtBWV30ICPEgqBg-wp0c8CAPV9k6J7wIa9_GtQfpWmhpE1zqFZyi2pQICPAg2pZLTVPGJbriiz0UhMytYDVYAXOgQnWDcrMOewK9O8cICPEgxm3QwzbvT4siJzubQGnST67bWv-exYwSPP1KDi7CaUwICPEgm6udUudfjUaM0gUFTylKGDMypj7ptMTG0zmxd_T5yTcICPAgMpOInkjFCVp1pOZhfZnyPAl8hdWGmHzQcrGLgLwSKLgICAAFiJYNc9cZAQPzpjs"],"envelope":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEIEoGWJOK_V5n2SfRtl7uUtVEkriirHjXK4HxwQexJtNrwIBKSkFHuv9bbpV2Nq0aSIBzDrmdQz07rKuynycreQn50CPAg3fyPzWLvSNo37XJwESGVJSni5-o0Scq02km2EeNDajEI8SDCVK9syvB50HOGmyseD6oDJgpyp8ka6T_cGS57uzmrZwjxIJgR-4m8-Q3_Z2GyRHXK5b11pUUloK5ra_eNwezlfAoUCPEgFa6sw-nGCjz6vEqErYq5JPYVdPtQEUoQW-a6KUGFotII8SCxPzWn869O0g7dbPeNGPp48oUUd-MQs-qTcF59d-kNywjxIB_8Nt5kaeAHJG1qp3MI751xQRro8K9q_v7kKdgv48GqCPEgtFEK0VubfP67YUyPihYaN9dTg9fCnso7LYYm40h86RMI8CBUfn8vND_FHy1q8eURvKLesQojCPxZvV5RtrwTxl9iVwjwIKD8mGRUgbk2Dt1xG-4OxMpCuw1ya5UEUQXsqASURGCtCPAgkPXX-naXR0fRIdS-sEDlzYmtMvSCNH42ESUF0QXb6NUI8CDQo_sIWZiWXaTGRSQBLmU-lHJKskYKqsjO1r02DhB8LAj_8Ajn9YmozHwo9QjwEJ46aM9ZDv3TdtqV3ZbRsNgI8SBOF8pILGf1kodr5MKmQs6Cd93joraGn3g6UPt_-kewPwjwIOG-gmM7bd_eR4AiDMNfluS3xvr7vicLR-sCBr5qtG2cCPAgrVNFrCoeQcCxhlmnE0BzHgR8HQpZAlfqzDDFzfWb8GUI8QRq0WWT8AjZJ2cF_c7k8ACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AI9ZMS1zxd7IEI8BDd00WgJZ0RncsC1Fyai_4aCPEgvxMFrnu7F05IW5INiraQ3OVEYMjNx6JfBxw1Q4jPLi4I8QRq0WWS8Ag2zxPAtI5JsP8Ag9_jDS75DI4uLWh0dHBzOi8vYWxpY2UuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZwjxIHAnv4KFFf4uiYEFJvLxiMxSyz8VowJP4roTfDD9h7bICPAgj5tgvbNF7mxSP4jGGE66ezUFRLnI4g1VTkvuV4VtCPAI8CCxlc1HuKORuHgn7DYIYcDhc4oo99OkTWBEvddBypoa7AjwIFcjjaF8kDNDYCZGaNISlRjvX-I7in-QNwsr4JYQbFJvCPAgnl0k4gs7LuY5i1umiHO-J7My3uBThLJUWQoY9LdVSrQI8SA6-Ft11_K_GqMNWYhkVsVqCFvXSYbp4S8JoLsLBnUzvgjxIBC8_mAE7JBP35SNxDBcG7joLJwURpMxdV2vSO64_jEOCPEge04Coj1xSi7CE8UwqiBGNhPyZ5QdD_YZwn-heSdObU4I8SBgdDSgr3VUx1j8m_pK7-OzMwwFgXeLy43ujffCv-hf5AjwIMl-PnAt4xjoBEVU4-nkyN0NKRa9AvX4kEMfllFyIJS9CPFZAQAAAAHz4rV-uwQFg02bVnEMUFgpIdGKjM4tWuID1kTVnrjisAAAAAAA_v___wJURAIAAAAAABYAFBFys2oc0-U-bYrC3VulGLzND5fbAAAAAAAAAAAiaiDwBHLTDgAICPEgMJIBYi46xOIuFDwzJ9nOx14ngW5HbglUf65ORpkoIYcICPAgHgGWEGCDHWgscwT92NOoJ7s-ezbPkyiWr2RnYZDC_dwICPAgtffMyyLu-MscJsDc0dzwGspwSrrmvVAnMNgsgWhHClgICPAgMUl1OfBDUwhp5VZjHwVA0nuz1F5HZTUJCHAnM1L1F3MICPAgStK7UWpnrUueV5EaE7uE0y6BLMp6EANmrbhrTqEBZu8ICPAg5LVW7IHtUL5mNOvPx1hOTfLMmqlQ7t9EFW-KDtrISIQICPAgABgXZ6upFU8qiDQKFtQFpqkjKwl0PsxM4JUjVLlDKbkICPAgEwb96FiOhjlbwI8GFZQ4a5GXwxs4bUdqVOMKrtBWV30ICPEgqBg-wp0c8CAPV9k6J7wIa9_GtQfpWmhpE1zqFZyi2pQICPAg2pZLTVPGJbriiz0UhMytYDVYAXOgQnWDcrMOewK9O8cICPEgxm3QwzbvT4siJzubQGnST67bWv-exYwSPP1KDi7CaUwICPEgm6udUudfjUaM0gUFTylKGDMypj7ptMTG0zmxd_T5yTcICPAgMpOInkjFCVp1pOZhfZnyPAl8hdWGmHzQcrGLgLwSKLgICAAFiJYNc9cZAQPzpjs"]},"log":{"leaf_index":"3516","tree_size":"3804","proof":["fd33058552b865286b971943d9d1cd1301c7ef3f3205669e031ac1a00e6688e6","328cc9ca102a44ba183ba4952655b61361597c71617c505c272925250036b3d3","0c4257f0ebf225c6d8a230508346af9af34123d0cf090d1d38d1e12556fddd82","101f3e94b324e75e265ed99793afb4c4e08a636fea5118143e7776e120668a70","c099a3f29cd99c68ef0ac83a28606d9c72cbf0ccc7c8cd5ea7ba582cd1506012","57df3cc0e4a09f04321f548eb71bd2dd36d09dbd3bcfa95bd9969e6dfb450c22","7b091eddf7d3bfbc8726958f5898937c94dfe58a1c761af5ed5e76c52a42722f","32c308752f9217b1c4a86dd18bd7c428e4bf0819f03bcecd3c244aeb14e5c028","5bc8f1bbb7a36ffa2afc301ec767424419006f77d79dfc7ac3adb0dab9eb36e8","98b5a14b42b3a202b6ef825f66833fa505601404c4c0f14575f3ec922607a858","af34d80d0065c0ab502282775e865492e2cb49c9493f4594d63ba5577922854a","3c578dccc15502c5f3efe228cadc99fee76ab536ed01f66b14d316fdcc157429"],"checkpoint":"pubphys.com/log/v1\n3804\nAK6t4qgu96+M9wScTrIlsJ10d/zhKVEtYguyM3aeJvo=\n\n— pubphys.com/log/v1 JFPwIPP8EtoxgcsQg7V7CwIdL4UKPqJtpv+eB8sFNJjyQHIdyA1VabmBsPyLqq2bLxJPn57rA6fQi8y0QDDjRXHvlQg=\n","promise":"pubphys.com/log/v1 promise\n93876c2a21dedec802531e28d42ffff03221c10d6037b90ccae70d00d04ea541\n3516\n2026-10-15T23:43:57Z\n2026-10-16T01:43:57Z\n\n— pubphys.com/log/v1 JFPwIOCT78wZwtM41t1g/7sIrOnJ0OHNnaWsMSoIg20TmMAkEuwSQSLdaWjxZ5uLikoxecGiwa47rrppqbLpgd+vXQk=\n"},"orcid_key_evidence":[],"attesting":null}